Suture in ophthalmic surgery


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  • The Anatomy of a Surgical Needle will now be considered. We shall examine the aspects illustrated. Needle Point : Penetration of a needle is dependant on the point. Each specific point is designed and produced to the required degree of sharpness to penetrate smoothly the types of tissues to be sutured. Chord Length : The straight line distance from the point of a curved needle to the swage. This can vary from 2mm to more than 2 inches. Length is a determining factor in the width of bite taken by the needle. Swage : This is the area in which the suture is attached to the needle. The swage area is of specific importance to the relationship of needle and suture thicknesses. It is also the weakest point of the needle. The objective of the swage area is to achieve the closest one-to-one suture needle ratio as possible. A one-to-one needle ratio reduces additional trauma which may be caused by the needle or the suture and in addition prevents leakage in anastomotic procedures. Needle Diameter : The gauge or thickness of the needle wire. Needle Diameter various from 30 microns to over 1mm The diameter equals the size of the needle track - except with spatulated or cutting designs. Needle Radius : If the curvature of the needle were to continue to make a full circle, the radius of the curvature is the distance from the centre of the circle to the body of the needle. Think of the needle as part of a circle.
  • Needles are available in various shapes to accommodate the desired depth of bite and the desired "turnout" in specific tissue . The available shapes are shown on the slide. Selection of the needle shape is dependent on the size and depth of the area to be sutured. Use of the 1/4 circle needle is often limited to ophthalmic and microsurgical procedures. A commonly used curved needle is the 3/8 Circle. These needles can be easily manipulated in relatively large and superficial wounds such as closure of the dermis. Because a large arc of manipulation is required , 3/8 Circle needles can be awkward or impossible to use in deep cavities such as the pelvis or in other small difficult to access locations. A 1/2 Circle needle is relatively easy to use in these confined locations, although it requires more rotation of the wrist than a 3/8 circle. The tip of a 1/2 circle needle can become obscured by tissue deep in the pelvic cavity for example. When this occurs the surgeon may have difficulty locating the point to reposition the needle holder and pull the needle through tissue. A 5/8 Circle needle may be useful in this situation, as may a 'J' needle. Straight needles are generally used for skin and compound curved needles for Ophthalmics.
  • Cutting Needles Cutting needles are required whenever dense or tough tissue is encountered. CONVENTIONAL CUTTING needles have the third cutting edge on the inside curvature of the needle . REVERSE CUTTING needles have a cutting edge on the outer convex curvature of the needle . Common applications for these needles are : Closure of skin and various plastic surgery applications and for orthopaedic procedures. Reverse cutting needles are stronger than conventional cutting needles because of their different triangular shape. PRIME NEEDLES are specialised skin needles which utilise a slimmer wire for use in finer applications. The unique hollow form point design improves penetration over needles of this type which were supplied for Plastic and cosmetic surgery. PRIME needles are available in both Conventional and Reverse cutting versions. P Needles are made of ethalloy – a stronger material which resists bending.
  • Round bodied needles are designed to separate tissue fibres rather than cut them. They are used in situations where easy splitting of tissue fibres is possible. They do not have cutting edges. TAPERPOINT NEEDLES are often preferred where the smallest possible hole in tissue and minimal tissue trauma is desired . Taper point needles are used primarily on soft tissues , such as peritoneum, abdominal fascia, blood vessels, ureters and subcutaneous tissue.
  • This slide outlines the key markings that are on the suture box. Each diagram / image is an important piece of information regarding the suture / needle.
  • Needle Body : Is the portion between point and swage and is used as the grasping area. Needle Arming : The needle should be grasped in the middle to 1/3 of the distance from the swage area to the point. The needle should be placed securely in the tip of the needle holder jaws. After the needle has penetrated the tissue, the needle holder can be used as shown to pull the needle and suture through. Good suturing technique dictates that the needle should only penetrate one side of the wound at a time , it should not bridge both sides of the wound.
  • Suture in ophthalmic surgery

    1. 1. Suture material properties•Tensile strength : it is duration of suture holding strength in the tissue . This can be tested by special devisecalled [tensiometer] and this done by holding the suture between 2 jaws (rolled edge) 8 cm apart then pullthe suture at speed 50 cm/min till the suture is broken and this procedure repeated 10 times then theaverage is taken ,by this way we can measure the elasticity and irreversible deformity of the suture•Absorbability : it is duration of suture degradation in the tissue .there are 2 types :1.Enzymatic degradation :elicit marked inflammatory reaction2.Hydrolytic degradation : cause less reactionBoth tensile strength and absorbability depend on type of suture material , suture size and tissueenvironment into which the suture is placed•Knot strength :it is the forced required for the knot to slip .•Configuration :1.Monofilament2.Multifilament•Elasticity : the degree of suture stretches and return to original length .•Memory or suture stiffness :high memory :mean suture stiffness ,difficult to handle with ,unties•Tissue reactivity : peak of inflammatory reaction in the first 2-7 days
    2. 2. IDEAL SUTURE PROPERTIESHandle comfortablyKnot safely without frayingMinimal tissue reactioneasy to SterilizedHave no electrolytic ,allergenic ,capillary or carcinogenic actionHigh tensile strengthShould be absorbed after serving it`s functionUnfortunately there is no single suture has all these properties ,so there is no single suture issuitable for all purposes.
    3. 3. Suture material division• Suture material can be divide into absorbable or non-absorbable , monofilament ormultifilament , biological or syntheticAbsorbable suture non-absorbable suture•Can be defined as the suture that losesmost of it`s tensile strength withen 2month•It undergoes either enzymatic orhydrolytic degradation ,the time it take forsuture to be absorbed vary with the type ofmaterial.•No foreign body lifted in the tissue•Usually elicit marked inflammatoryreaction•It`s effective tensile strength remain forseveral month or even permanent•It has reduce or absent degradation .•Foreign body is lifted in the tissue•Usually it is inert with minimal tissuereaction
    4. 4. Suture material divisionmonofilament multifilament•Has smooth surface that provide easy passagethrough the tissue•Does not support bacterial growth•Has no capillary action•It is slipary ,stretchy, difficult to handle with•It has stiff end that cause irritation if the knot isnot buried•it has coarse traumatic surface that provide tissuedrag•The potential spaces between the filament act asnidus of infection•Has capillary action that prone for leakage of fluidfrom the tissue•Not elastic easy to handle with and safely tying•Soft and pliable well tolerated by the patient
    5. 5. Absorbable sutures [natural]• Plain gut :it is natural absorbable suture made from highly purified connective tissue(mostly collagen) derived from mucosal and submucosal layers of sheep and beef intestineIt has low tensile strength ( < 1 week ) and may absorbed rapidly in the infective tissue or area with highenzyme levelIt undergoes enzymatic degradation and usually elicit marked inflammatory reaction and may even provokeallergic reaction• It may be used in wiess`s procedure to evoke inflammation and fibrosis• Chromic gut : it is similar to plain gut but cover with chromic salt ,the covering chromic salt willprolong it`s tensile strength ( 2-3 week) ,decrease tissue reaction ,increase resistance to body enzymes .It is also used in weiss`s procedure .• Collagen : this derived from flexor tendon of beef ,it is more consistent in strength and smoothersurface and also elicit less reaction than gut sutureit is also available in plain collagen ( < 1 week) and chromic collagen ( 2-3 week) .
    6. 6. Absorbable suture (synthetic)• Polyglactin 910 (vicryl ): Vicryl made from polyglycolic acid + lactic acid ,it is available in monofilament and braided multifilament Coated vicryl (or vicryl plus ) is covered with polyglactin 370 +calcium stearate (the coating make thesuture smoother and softer thus decrease tissue drag ) Tensile strength : 2-3 weeks Complete absorption occur after 2-3 month Undergoes hydrolytic degradation It is commonly used in strabismus surgery and conjectival closure• Polyglycolic acid(dexon): There are 2 types :1- dexon s :is braided polyglycolic acid without coating2- dexon plus :treated with surface lubricant poloxamer 188 Tensile strength : 2-3 weeks Complete absorption occur after 2-3 month It is rarely used in anterior segment surgery .
    7. 7. Absorbable suture (synthetic)• Polydiaxanon (pds ): It is either mono or braided multifilament made from polyester and polydiaxanon Pds is ideal for internal tissue whenever long lasting absorption is required It has very stiff end Tensile strength : 4-6 weeks Complete absorption occur after 6 month There is a new study to develop a self knotting suture made from polydiaxanon with bidirection barbs ,but this not useful for many purposes (the smolest suture available is 6/0 ) , in this study they considerknotting is time consuming and the knot it self act as potential space for bacterial growth .• Polytrimethylene carbonate (maxon ): It is stronger than pds and better knot tying than vicryl . Tensile strength : 4-6 weeks All synthetic absorbable suture undergo hydrolytic degradation with mild inflammatoryreaction during absorption process .
    8. 8. Non-absorbable suture• Silk : Silk is natural multifilament derived from spider coccon , there are 2 types :1- virgin silk :it is fibrin coated with sericin (with gum) twisted together2- braided silk : remove all the gum and wax (sericin is removed) then braided together Tensile strength : 3-6 month Complete absorption may occur after several years but still considered as non-absorbable suture It elicit moderate inflammatory reaction It is not elastic so easy to handle and safely tying ,it is also the most soft and pliable that well toleratedby the patient .• Polyamid (nylon)(ethilon) : It is the commonest suture that used in microsurgery becuose of it`s consistent tensile strength ,smoothand even surface and it`s good knotting property . It is relatively elastic with stiff end ,that why the knot must be burried It is monofilament made from polyamid 6.6 . It loses 10-15 % of it`s tensile strength every year . Commonly used to close corneal wound .
    9. 9. Non-absorbable suture• Polypropylene ( prolene ) : It is the most elastic monofilament with very stiff end that erode through the incision ,so mustburried well It retain tensile strength over 2 years Inert and elicit minimal reaction It has non-hydrolytic ,so not affected by body fluid Useful for suturing non-healing structure e.g. iris wound , intra-ocular lens to iris fixation .• Polyester : It is the strongest and least elastic suture that has perminent tensile strength ,that why it iscommonly used retinal surgery . There are 2 types :1- braided polyester ( mersilene )2- coated polyester (ethibond ) coated with small amoant of polybutylate• Polybutester ( novafil ) :Slightly elastic ,with high tensile strength that last years .• Polyvinylidene fluoride ( PVDF ):it is monofilament similar to prolene but with better and tighter knot .
    10. 10. Suture size { gauge }The size of the suture refer to the diameter the suture strand ,and this can be measured by to ways1- usp :adapted by united state pharmacopoeia ,in which the diameter denoted as zero ,the more zero thesmaller size suture ( 4/0 larger than 5/0)2- metric measurement :it is the newest and adapted by European and USP ,in which the suture diametermeasured in mm .(it is more accurate ) .Metric number USP0. Virgin silk8/07/06/05/04/03/02/00
    11. 11. SURGICAL NEEDLES• Prior to 1959 eyed needles was commonly used in USA ,the problem with eyed needle threaded withsuture that double thickness suture will pulled through the needle tract ,however ,only single thicknesssuture is lifted tied in the incision ,this lead to needle tract larger in diameter than the suture ,and thisprone for leaking of fluid and entering of infection .• At 1914 swaged needle manifuctured (which mean permanent attachment of the suture to the needleat the time of mannifacture ) . There are 2 basic styles for needle swage :1- laser drill :forming a hole in the trailing end of the needle into which the suture is fixated .2- channel fixation :making planed cut that is half the thickness of the needle along the trialing end and thesuture is fixed to a depression in the cut area .The disadvantage of channel fixation is that the suture can be loosen or the swage deformed if grasped byneedle holder ,so laser drill is preferable .
    12. 12. Anatomy of a Surgical Needle
    13. 13. Needle Shapes•Eye•Microsurgery•Dura•Eye•Fascia•Nerve•Muscle•Eye•Skin•Peritoneum•Cardiovascular•Oral•Pelvis•Urogenital tract•Nasal cavity•Nerve•Skin•Tendon•Eye (Anteriorsegment)•Laparoscopy
    14. 14. Ideal needle properties• Sufficiently rigid : to resist bending and ductility but not so rigid that breake easyif stressedDuctility mean the amount of deformation that the needle can withstand withoutbreake• Long enough :to be grasped by needle holder without blunt the point• Sufficient diameter and sharp edges :to form large enough tract to allow theknot to be burry .• Not traumatic as possible
    15. 15. common needle in ophthalmplogy• Cutting : Configuration :triangular with 3rdedge in the inner (top) surface ,so the cutting will be at the tip and 3edges It track`s superfecialy so may pull out the tissue during passage of the needle Used in tough tissue ,full thickness bite .Reverse cutting : Configuration :traingular with 3rdedge at the outer (buttom)surface ,so the cutting will be at the tipand 3 edges . It track`s deeply ,so accidental perforation may occur with partial thickness suture e.g. rectus –scleralfixation It is ideal for oculoplastic surgery as it pass easy through the epidermisPrime needle : It is modified cutting or reverse cutting with peveled edge ,this narrow edge make the needle very shapbut affect easy with tissue density (bend easy).
    16. 16. Cutting Needles• Conventional Cutting• Reverse Cutting• PRIME• P Needle
    17. 17. needles Spatula : Configuration :trapezoid with 4-6 sides ,so the cutting will be at the tip and the sides This configuration allow the needle to split the tissue lamella and stay in the intralamellarplane ,so avoid accidental perforation . Most commonly used in anterior segment Surgery e.g. cataract ,sequint surgery .Taper point : It has round body that taper to the point ,so cutting will be at the tip only . Round body needle designed to separate tissue fiber rather than cutting them It used in delicate tissue e,g., iris It produce the smallest hole of all needles ,so used wherever water tight seal is required e.g.conjectival flap in trabelectomy .Taper cut :It has round body with cutting edges at the point only to facilitate penetration
    18. 18. Round Bodied Needles• TAPERPOINT
    19. 19. Packaging…Expiry dateBatch NumberDo Not Re-useProduct (re-order) CodeImperial GaugeMetric GaugeNeedle size& curvatureNeedle typeNeedle pointSee Instructionsfor useNeedle profileSterilisedEthylene Oxide
    20. 20. Use of Needle HoldersLoadingNeedleNeedlepassingthroughskin